Serotonin 5-HT2C receptor is one of the receptors of the biological transmitter serotonin, which is distributed mainly in the central nervous system and controls many physiological functions in vivo. A representative example is the control of appetite. It has been demonstrated in a study using rodents that stimulation of the central serotonin 5-HT2C receptor decreases eating behavior, resulting in decreased body weight. It has also been reported that, in human as well, administration of a serotonin 5-HT2C receptor activator suppresses appetite and decreases body weight (see non-patent document 1). In addition, it has been demonstrated in a rat test using a serotonin 5-HT2C receptor activator that stimulation of the central serotonin 5-HT2C receptor suppresses depression-related behaviors (see non-patent document 2), and has also been reported to be effective for many central nervous diseases such as anxiety etc. (see non-patent document 3). The serotonin 5-HT2C receptor is also highly expressed in the parasympathetic nucleus and motorial nerve cell bodies in the sacral spinal cord, and is considered to control the peripheral nervous functions (see non-patent document 4). It has been reported that when a serotonin 5-HT2C receptor activator is administered to rats, penile erection is induced (see non-patent document 5), and urethral resistance is increased (see patent document 1); all these actions are attributed to stimulation of the serotonin 5-HT2C receptor in the sacral spinal cord. For serotonin 5-HT2C receptor activators, many clinical applications are likely, with particular expectations for anti-obesity drugs, anti-depressants, anti-anxiety drugs, therapeutic drugs for male erectile dysfunction, and therapeutic drugs for stress urinary incontinence and the like.
“Pelvic organ prolapse” is a disease wherein a pelvic organ descends and protrudes from the vaginal orifice, and is known to include prolapse of anterior vaginal wall, posterior vaginal wall, uterus, the vaginal cuff scar after hysterectomy, rectum, small intestine, bladder or urethra, which are called anterior vaginal wall prolapse, posterior vaginal wall prolapse, uterine prolapse, prolapse of the apical segment of the vagina, rectal prolapse [rectocele], enterocele, cystocele and urethral prolapse, respectively (see, for example, non-patent documents 30-32). The pelvic organ prolapse becomes conspicuous when abdominal pressure rises transiently as a result of straining or bearing a heavy load and the like. Childbirth, aging, and obesity are known risk factors of pelvic organ prolapse and one of suggested causes thereof is the weakening of the pelvic floor muscles and perivisceral connective tissue that support the vagina, the uterus and the like. The pelvic floor muscles are skeletal muscles that unite with the pelvis in a hammock-like way, serving constantly to maintain some contraction and support the organs in the pelvis from below. In pelvic organ prolapse, these pelvic floor muscles are weakened to be unable to support the pelvic organs against their weights, resulting in the descent of the organs (see, for example, non-patent documents 30-32). Particularly, when abdominal pressure rises, the prolapse becomes more conspicuous because of insufficient opposing force to the increased abdominal pressure. On the other hand, it has been reported that when abdominal pressure rises, the urinary bladder is compressed, reflex via the urinary bladder—spinal cord—pelvic floor muscles and the urethra causes the contraction of the pelvic floor muscles and the urethral sphincter to increase urethral internal pressure, whereby urinary incontinence is prevented (see, for example, non-patent document 33). For this reason, it is considered that upon a rise in abdominal pressure, the pelvic floor muscles contract reflexly to prevent not only urinary incontinence, but also the descent of the pelvic organs. If there is a failure in this reflex pathway or the pelvic floor muscles, sufficient contraction of the pelvic floor muscles cannot be obtained and support for the organs becomes inadequate. Therefore, a therapeutic drug for pelvic organ prolapse can be screened by the evaluation of contractile responses of the pelvic floor muscles.
The lower urinary tract symptoms consist of storage symptoms, voiding symptoms and post micturition symptoms, and one of the main post micturition symptoms is post-micturition dribble. Post-micturition dribble is a complaint of involuntary loss of urine immediately after one has finished passing urine, which generally takes place after leaving toilet in men and after rising from the toilet in women. Pelvic floor muscle exercise is reported to be effective for the post-micturition dribble (see non-patent documents 34-36), and such dribble is considered to be related to weakened pelvic floor muscles. Therefore, a therapeutic drug for post-micturition dribble can also be screened by the evaluation of the contractile responses of the pelvic floor muscles.
In the meantime, compounds having structures similar to the benzoxazepine derivative described in the specification of this application have been reported in non-patent document 6-non-patent document 29, and patent documents 2-25.    non-patent document 1: Expert Opinion on Investigational Drugs, 2006, vol. 15, p. 257-266    non-patent document 2: J. Pharmacol. Exp. Ther., 1998, vol. 286, p. 913-924    non-patent document 3: Pharmacology Biochemistry Behavior, 2002, vol. 71, p. 533-554    non-patent document 4: Neuroscience, 1999, vol. 92, p. 1523-1537    non-patent document 5: Eur. J. Pharmacol., 2004, vol. 483, p. 37-43    non-patent document 6: Izvestiya Vysshikh Uchebnykh Zavedenii, Khimiya i Khimicheskaya Tekhnologiya (2005), 48(4), 142-147    non-patent document 7: Bioorganic&Medicinal Chemistry (2005), 13(6), 1901-1911    non-patent document 8: Journal of Medicinal Chemistry (2004), 47(11), 2776-2795    non-patent document 9: Chem. Bio. Chem. (2004), 5(4), 508-518 non-patent document 10: ARKIVOC (Gainesville, Fla., United States) (2003), (7), 161-179    non-patent document 11: Polish Journal of Chemistry (2000), 74(1), 141-145    non-patent document 12: Bioorganic&Medicinal Chemistry Letters (1999), 9(3), 481-486    non-patent document 13: Journal of Medicinal Chemistry (1996), 39(18), 3539-3546    non-patent document 14: Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1994), (20), 2993-9    non-patent document 15: American Journal of Physiology (1993), 265 (1, Pt. 1), C143-C155    non-patent document 16: Journal of the Chemical Society, Chemical Communications (1993), (7), 607-8    non-patent document 17: Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry (1989), 28B(7), 592-4    non-patent document 18: Inorganic Chemistry (1989), 28(25), 4531-5    non-patent document 19: Inorganica Chimica Acta (1985), 99(1), L5-L7    non-patent document 20: Journal of Medicinal Chemistry (1982), 25(6), 735-42    non-patent document 21: Bulletin des Societes ChimiquesBelges (1976), 85(11), 898-903    non-patent document 22: Annali dell'Istituto Superioredi Sanita (1973), 9, Pt 2-3, 150-9    non-patent document 23: Journal of Medicinal Chemistry (1973), 16(10), 1124-8    non-patent document 24: Khimiya Geterotsiklicheskikh Soedinenii (1971), 7(9), 1288-92    non-patent document 25: Gazzetta Chimica Italiana (1971), 101(2), 167-72    non-patent document 26: Tetrahedron Letters (1970), (12), 947-50    non-patent document 27: Journal of Pharmaceutical Sciences (1969), 58(12), 1460-3    non-patent document 28: Helvetica Chimica Acta (1963), 46, 1696-704    non-patent document 29: Farmaco, Edizione Scientifica (1959), 14, 159-75    non-patent document 30: Journal of The Japan Neurogenic Bladder Society 2003, vol. 14, p. 278-289    non-patent document 31: Lancet 2007, vol. 369, p. 1027-38    non-patent document 32: Europian Urology 2007, vol. 51, p. 884-886    non-patent document 33: American Journal of Physiology Renal Physiology 2004, vol. 287, p. F434-441    non-patent document 34: British Journal of Urology 1997, vol. 79, p. 892-7    non-patent document 35: Urologic Nursing 2004, vol. 24, p. 490-7, 512    non-patent document 36: British Journal of Nursing 2005, vol. 14, p. 1014-8, 1020-1    patent document 1: WO2004/096196    patent document 2: US2006/0069087    patent document 3: WO2005/115145    patent document 4: US2005/0038032    patent document 5: WO2004/094371    patent document 6: WO2004/069244    patent document 7: WO2004/014851    patent document 8: WO2003/013545    patent document 9: WO2002/051838    patent document 10: WO2002/051232    patent document 11: WO2002/036555    patent document 12: WO2002/018377    patent document 13: WO2001/055118    patent document 14: WO98/50382    patent document 15: WO98/47876    patent document 16: WO98/46590    patent document 17: WO97/17344    patent document 18: EP567090    patent document 19: U.S. Pat. No. 4,125,538    patent document 20: DE2116222    patent document 21: DE2014223    patent document 22: SU245787    patent document 23: U.S. Pat. No. 3,542,807    patent document 24: FR1463402    patent document 25: BE669838